Spin-Formed Rocket Engine Liners for Low-Cost Regenerative Cooling
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Solution Overview
Problem
Current liquid rocket engine manufacturing methods are costly and complex, with high expenses in milling large metal alloys and integrating injector heads and coolant manifolds, which increases weight and reduces efficiency due to high temperature and pressure gradients.
Innovation Solution
The method involves CNC spin forming of metal alloys to create domed tubes for both inner and outer shell liners, with an injector head assembly that simplifies the construction process, reduces weight, and enhances cooling by creating a gap between the liners for propellant flow, using fasteners, seals, and welds for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional milling methods are used to manufacture rocket engines from large metal alloy blanks, then manufacturing precision can be achieved, but manufacturing cost and complexity increase significantly
Solution Approach 1:
The patent replaces traditional mechanical milling processes with spin forming technology. Instead of removing material through complex multi-axis milling operations, the invention uses a spin former to form the combustion chamber and nozzle directly from a cylindrical blank through rotational forming, dramatically simplifying the manufacturing process while maintaining precision
Solution Approach 2:
The invention changes the manufacturing approach from subtractive (milling) to formative (spin forming). By altering the fundamental manufacturing parameter from material removal to plastic deformation and forming, the process complexity is reduced while achieving the required geometric precision for rocket engine components
2Reliability
If traditional integration methods are used for injector heads and coolant manifolds, then functional requirements are met, but engine weight increases
Solution Approach 1:
The patent integrates the injector head and coolant manifold functions directly into the combustion chamber structure through spin forming. Instead of separate heavy components requiring complex integration, the cooling channels and injector features are formed as integral parts of the chamber, reducing weight while maintaining cooling effectiveness
Solution Approach 2:
The combustion chamber is designed to serve multiple functions simultaneously: combustion containment, structural support, and integrated cooling. The spin-formed structure incorporates cooling channels and injector mounting features directly, making the chamber a multi-functional component that eliminates the need for separate heavy integration components
3Force
If high head pressure is applied to the combustion chamber, then thrust increases, but temperature and pressure gradients cause excessive heat and wear
Solution Approach 1:
The patent implements self-cooling where the combustion chamber structure itself serves as the cooling system. Spin-formed cooling channels are integrated directly into the chamber walls, allowing coolant to flow through the structure and self-regulate temperatures, enabling high head pressure operation without excessive heat accumulation
Solution Approach 2:
The spin-formed cooling channels act as intermediaries between the hot combustion gases and the chamber structure. These channels provide a coolant pathway that mediates heat transfer, allowing the chamber to withstand high pressures and temperatures by conducting heat away through the integrated cooling system
4Productivity
If complex manufacturing processes are used, then performance can be optimized, but cost per launch increases
Solution Approach 1:
The patent replaces complex multi-step mechanical manufacturing processes with a single spin forming operation. This substitution maintains the ability to produce high-performance geometrically complex components while dramatically reducing manufacturing steps, tooling requirements, and associated costs
Solution Approach 2:
The invention segments the manufacturing process into a simple two-step sequence: spin forming the combustion chamber with integrated features, then minimal post-processing. This segmentation eliminates the need for complex sequential operations like multiple milling setups, tool changes, and manual assembly, reducing both cost and time while maintaining performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in a simpler, less expensive rocket engine design with improved thrust-to-weight ratio and reduced maintenance costs, while maintaining performance by efficiently managing heat and pressure through the spin-formed structure.
Implementation Method 1
CNC spin forming of a sheet or tube of a first metal alloy into a first domed metal alloy tube
Implementation Method 2
leaving a gap between the inner and outer shell liners for propellant to flow to cool the engine and, in particular, the inner shell liner
Implementation Method 3
laser sintered, resulting in dual liner rocket engine with embedded axially disposed cooling channels
Data Source
AI summary
A method for manufacturing a liquid fueled rocket engine involves forming a first flange in apposition to a top end of a first tube, fixing an injector head to the first flange to form an inner shell liner assembly, shaping the inner shell liner assembly, forming a second flange in apposition to a top end of a second tube, positioning the inner shell assembly inside the second flanged tube and fixing the second flange to the injector head. Rocket engines manufactured using the method have performance superior to existing rocket engines in at least one parameter.